After much frustration using the Amazon SOAP API, I have finally got Flash talking to it (albeit in a round about way).

What I chose to do was to use Cold Fusion MX components and Flash Remoting to talk to Amazon. I created a component in Dreamweaver to talk to the web service. The CFMX component then sends the data returned from the service to the Flash movie for processing.

Here is the trick: When talking to the Amazon API, you can not just invoke the function through the proxy with a couple of parameters that are strings. You must create a new structure in Cold Fusion and then pass that structure to the service.